1. Field of the Invention
A method for detecting and repairing isolated errors in a stream of digital data samples derived from an over-sampled analog signal.
2. Discussion of the Prior Art
Analog signals derived from measuring or sensing devices may be digitized as a series of digital data samples. The digital data samples may be telemetered to a remote observation site or recorded on a digital storage device such as a memory or a magnetic tape.
During telemetric transmissions or recording, bit dropouts occur or perhaps some form of interference imparts a false value to a data sample. Usually, such errors involve only a single isolated sample of the digital data stream. The term "isolated" means that there are no other errors immediately prior to or subsequent to the sample under consideration.
Most error correction methods fit a spline function or other type of smoothing function over several samples before and after a detected error. The erroneous sample is then replaced by an interpolated value from the smoothing function. Part of the problem is to detect the error without first making a visual inspection of the data.
It is an object of this invention to detect and repair an isolated error in a discrete digital data stream or time series without interrupting the data flow.